find_unused_helpers.rb

#!/usr/bin/env ruby
#
# Shotgun approach (read: slow and dirty hack) to help find unused helpers in a Rails application
#

puts "Loading all source files into memory :("
source = {}

Dir["app/**/**/*.*"].each do |f|
  next if f.include?("app/assets")
  source[ f ] = File.readlines(f)
end

puts "#{source.size} files loaded into memory"

helpers = []

source.keys.grep(/app\/helpers/).each do |f|
  code = source[ f ]
  code.each do |line|
    if line =~ /def ([^\(\s]+)/
      helpers << $1.chomp
    end
  end
end

puts "Scanning for #{helpers.size} helpers"

# combine the source code
complete_code = source.values.flatten

# Find occurances
helpers.each do |name|
  found = false

  complete_code.each do |line|
    next if line =~ /def #{name}/
    found = true if line =~ /#{name}/
  end

  puts "No traces found of #{name}" unless found
end